V. P. Motornyi, “On the exact constants in Hardy – Littlewood inequalities”, Ukr. Mat. Zhurn., vol. 69, no. 12, pp. 1625–1632, Dec. 2017, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/1809